/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.android.dx.dex.code;

import com.android.dx.rop.cst.CstType;
import com.android.dx.util.FixedSizeList;
import com.android.dx.util.Hex;

/**
 * Ordered list of (exception type, handler address) entries.
 */
public final class CatchHandlerList extends FixedSizeList implements
		Comparable<CatchHandlerList> {

	/** {@code non-null;} empty instance */
	public static final CatchHandlerList EMPTY = new CatchHandlerList(0);

	/**
	 * Constructs an instance. All indices initially contain {@code null}.
	 * 
	 * @param size
	 *            {@code >= 0;} the size of the list
	 */
	public CatchHandlerList(int size) {
		super(size);
	}

	/**
	 * Gets the element at the given index. It is an error to call this with the
	 * index for an element which was never set; if you do that, this will throw
	 * {@code NullPointerException}.
	 * 
	 * @param n
	 *            {@code >= 0, < size();} which index
	 * @return {@code non-null;} element at that index
	 */
	public Entry get(int n) {
		return (Entry) get0(n);
	}

	/** {@inheritDoc} */
	public String toHuman() {
		return toHuman("", "");
	}

	/**
	 * Get the human form of this instance, prefixed on each line with the
	 * string.
	 * 
	 * @param prefix
	 *            {@code non-null;} the prefix for every line
	 * @param header
	 *            {@code non-null;} the header for the first line (after the
	 *            first prefix)
	 * @return {@code non-null;} the human form
	 */
	public String toHuman(String prefix, String header) {
		StringBuilder sb = new StringBuilder(100);
		int size = size();

		sb.append(prefix);
		sb.append(header);
		sb.append("catch ");

		for (int i = 0; i < size; i++) {
			Entry entry = get(i);

			if (i != 0) {
				sb.append(",\n");
				sb.append(prefix);
				sb.append("  ");
			}

			if ((i == (size - 1)) && catchesAll()) {
				sb.append("<any>");
			} else {
				sb.append(entry.getExceptionType().toHuman());
			}

			sb.append(" -> ");
			sb.append(Hex.u2or4(entry.getHandler()));
		}

		return sb.toString();
	}

	/**
	 * Returns whether or not this instance ends with a "catch-all" handler.
	 * 
	 * @return {@code true} if this instance ends with a "catch-all" handler or
	 *         {@code false} if not
	 */
	public boolean catchesAll() {
		int size = size();

		if (size == 0) {
			return false;
		}

		Entry last = get(size - 1);
		return last.getExceptionType().equals(CstType.OBJECT);
	}

	/**
	 * Sets the entry at the given index.
	 * 
	 * @param n
	 *            {@code >= 0, < size();} which index
	 * @param exceptionType
	 *            {@code non-null;} type of exception handled
	 * @param handler
	 *            {@code >= 0;} exception handler address
	 */
	public void set(int n, CstType exceptionType, int handler) {
		set0(n, new Entry(exceptionType, handler));
	}

	/**
	 * Sets the entry at the given index.
	 * 
	 * @param n
	 *            {@code >= 0, < size();} which index
	 * @param entry
	 *            {@code non-null;} the entry to set at {@code n}
	 */
	public void set(int n, Entry entry) {
		set0(n, entry);
	}

	/** {@inheritDoc} */
	public int compareTo(CatchHandlerList other) {
		if (this == other) {
			// Easy out.
			return 0;
		}

		int thisSize = size();
		int otherSize = other.size();
		int checkSize = Math.min(thisSize, otherSize);

		for (int i = 0; i < checkSize; i++) {
			Entry thisEntry = get(i);
			Entry otherEntry = other.get(i);
			int compare = thisEntry.compareTo(otherEntry);
			if (compare != 0) {
				return compare;
			}
		}

		if (thisSize < otherSize) {
			return -1;
		} else if (thisSize > otherSize) {
			return 1;
		}

		return 0;
	}

	/**
	 * Entry in the list.
	 */
	public static class Entry implements Comparable<Entry> {

		/** {@code non-null;} type of exception handled */
		private final CstType exceptionType;

		/** {@code >= 0;} exception handler address */
		private final int handler;

		/**
		 * Constructs an instance.
		 * 
		 * @param exceptionType
		 *            {@code non-null;} type of exception handled
		 * @param handler
		 *            {@code >= 0;} exception handler address
		 */
		public Entry(CstType exceptionType, int handler) {
			if (handler < 0) {
				throw new IllegalArgumentException("handler < 0");
			}

			if (exceptionType == null) {
				throw new NullPointerException("exceptionType == null");
			}

			this.handler = handler;
			this.exceptionType = exceptionType;
		}

		/** {@inheritDoc} */
		@Override
		public int hashCode() {
			return (handler * 31) + exceptionType.hashCode();
		}

		/** {@inheritDoc} */
		@Override
		public boolean equals(Object other) {
			if (other instanceof Entry) {
				return (compareTo((Entry) other) == 0);
			}

			return false;
		}

		/** {@inheritDoc} */
		public int compareTo(Entry other) {
			if (handler < other.handler) {
				return -1;
			} else if (handler > other.handler) {
				return 1;
			}

			return exceptionType.compareTo(other.exceptionType);
		}

		/**
		 * Gets the exception type handled.
		 * 
		 * @return {@code non-null;} the exception type
		 */
		public CstType getExceptionType() {
			return exceptionType;
		}

		/**
		 * Gets the handler address.
		 * 
		 * @return {@code >= 0;} the handler address
		 */
		public int getHandler() {
			return handler;
		}
	}
}
